The invention deals with a cyclone heat exchanger for preheating of powdered raw material, where the exchanger is consisting from a set of cyclones, which are mutually on different height level, and the cyclones are connected in series and they are connected with the tubes of hot gas such a way that the input of the first cyclone is connected to the hot gas source and the output of each cyclone is assigned to the input of the next cyclone and the raw material output from each cyclone is led to the beginning of hot gas tube from the previous cyclone.
The up to now known heat exchangers for preheating of powdered raw material before its next processing, for instance for preheating of raw material farina at dry method of cement clinker production, are realized with in series arranged heat exchanging stages. They are arranged mutually in series over each other, whatxe2x80x94especially at units with greater heat gradient and so with greater number of heat exchanging stagesxe2x80x94is highly demanding for the building work and for the assembly of corresponding equipment and which besides other is manifesting with inconvenient increase of costs to the unit of end product.
The problem of undesirable building height can be solved so, that the in series arranged heat exchanging cyclones are located beside each other and the individual gas tubes, which are interconnecting them, have to considerably descend under the level of individual cyclones. That means however a substantially increased extent of the propre technologic equipment and additionally that is to the expense of a fluent material movement and heating up gases during the technologic process, which once more manifests in an increase of investment and operation costs.
The disadvantages of up to now realized design arrangements are in substantial extent removed by the object of the invention, which is a cyclone heat exchanger for preheating of powdered raw material, composed from a set of cyclones, which are connected in series and interconnected with hot gas tubes such a way, that the input of the first cyclone is connected to the hot gas source and the output of each cyclone is assigned to the input of the next cyclone and the raw material output from each cyclone is led to the tube, assigned to the hot gas output from the previous cyclone.
The principle of the invention is that the set of cyclones is divided to two parts, a high temperature part nearer to the hot gas source, and a low temperature part and where each part is composed from at least two cyclones and which are mutually interconnected with a connecting tubing, on the end closer to the low temperature part of which a return loop is built up such a way that its lowest part is laying under the level of lower cyclone on the low temperature part, and that the high temperature part and the low temperature part are mutually located so that the connection of the warm gas inlet of the highest cyclone of high temperature part is situated higher as the connection of the warm gas inlet of the lower cyclone of the low temperature part, whereas the output of powdered raw material of the next cyclone of low temperature part is led to the ascending part of the return loop, whereas the high temperature part is further equipped with a transport tube to which the output tube of lower cyclone of low temperature part is led and which is led to the tube connecting the hot gas input of the highest cyclone of high temperature part and hot gas output from the previous cyclone. Here the input part of the transport tube is advantageously situated under the powdered raw material output level of the lower cyclone of the low temperature part.
An other principle of the invention is that the high temperature part and/or the low temperature part consists from at least two cyclones.
Finally the principle of the invention is, that into the output tube, arranged between the input chamber of the rotary kiln and the first cyclone of high temperature part a fuel input and a combustion air is led, eventually that to the output tube, arranged between the rotary kiln input chamber and the first cyclone of high temperature part, an input of hot gas and precalcinated raw material is led.
With arrangement according to the invention a substantial building height reduction of the cyclone exchanger at optimal exploitation of heat which is contained in gas led to the powdered raw material transport tube is achieved. As to the substantially less building height the invention can be additionally advantageously applied in areas with increased seismic activity, where for instance the usual high constructions could not be realized.
An other advantage of the solution according to invention is, that it can be used at calcinating exchangers, where for instance it is possible into the output gas tube between the rotary kiln and the lower cyclone of heat exchanger to lead additionally fuel and combustion air or gas with precalcinated raw material from the connected calcinating device.